Bioenergertics Flashcards
What is the photosynthesis equation?
carbon dioxide + water =
glucose + oxygen
What type of reaction is photosynthesis ? Explain why?
photosynthesis as an
endothermic reaction in which energy is transferred from the environment to the chloroplasts by light
How does temperature effect the rate of photosynthesis?
Plants can photosynthesise over a wide range of temperatures from 0°C to around 50°C.
The optimum temperature for most plants is 15°C to around 40°C.
Temperature affects the rate of photosynthesis in crop plants and affects where certain crops can be grown.
How does light intensity effect the rate of photosynthesis?
Without enough light, a plant cannot photosynthesise very quickly - even if there is plenty of water and carbon dioxide.
Increasing the light intensity increases the rate of photosynthesis, until some other factor - a limiting factor - becomes in short supply.
How does carbon dioxide concentration effect the rate of photosynthesis?
Carbon dioxide – with water – is one of the reactants in photosynthesis.
If the concentration of carbon dioxide is increased, the rate of photosynthesis will therefore increase.
Again, at some point, a factor may become limiting.
How does the amount of chlorophyll effect the rate of photosynthesis?
Chlorophyll absorbs the light energy required to convert carbon dioxide and water into glucose.
Chlorophyll is green - so absorbs the red and blue parts of the electromagnetic spectrum and reflects the green part of the spectrum. Leaves with more chlorophyll are better able to absorb the light required for photosynthesis.
What is the glucose produced in photosynthesis used for?
- used for respiration
- converted into insoluble starch for storage
- used to produce fat or oil for storage
- used to produce cellulose, which strengthens the cell wall
- used to produce amino acids for protein synthesis.
To produce proteins, plants also use nitrate ions that are absorbed
from the soil
What is respiration?
Respiration in cells can take place aerobically (using oxygen) or anaerobically (without oxygen), to transfer energy.
What do organism need energy for?
- chemical reactions to build larger molecules
- movement
- keeping warm.
What is the equation of Aerobic respiration?
glucose + oxygen = carbon dioxide + water
What is the equation for Anaerobic respiration in muscles?
glucose = lactic acid
Why is less energy transferred in anaerobic respiration?
As the oxidation of glucose is incomplete in anaerobic respiration much less energy is transferred than in aerobic respiration.
What is the equation for anaerobic respiration in plant and yeast cells ?
glucose = ethanol + carbon dioxide
What is fermentation and what is it used for?
Anaerobic respiration in yeast cells is called fermentation and has economic importance in the manufacture of bread and alcoholic drinks.
What happens when humans do exercise?
During exercise the human body reacts to the increased demand for energy.
The heart rate, breathing rate and breath volume increase during exercise to supply the muscles with more oxygenated blood.
How does anaerobic respiration take place?
If insufficient oxygen is supplied anaerobic respiration takes place in
muscles. The incomplete oxidation of glucose causes a build up of lactic acid and creates an oxygen debt. During long periods of
vigorous activity muscles become fatigued and stop contracting efficiently.
What is oxygen debt?
Oxygen debt is the amount of extra oxygen the body needs after exercise to
react with the accumulated lactic acid and remove it from the cells.
How is lactic acid converted back into glucose?
Blood flowing through the muscles transports the lactic
acid to the liver where it is converted back into glucose.
What is metabolism?
Metabolism is the sum of all the reactions in a cell or the body. The energy transferred by respiration in cells is used by the organism for the continual enzyme controlled processes of metabolism that synthesise new molecules.
What does Metabolism include?
- conversion of glucose to starch, glycogen and cellulose
- the formation of lipid molecules from a molecule of glycerol
and three molecules of fatty acids - the use of glucose and nitrate ions to form amino acids which in turn are used to synthesise proteins
- respiration
- breakdown of excess proteins to form urea for excretion.
